A method for determining performance of an application in a system is described herein. The method includes receiving performance data of the application, the performance data includes a plurality of types of transactions performed by the application, a counted number of transactions for each of the plurality of transaction types as performed by the application, and a total service time by the system of the counted number of transactions of each of the plurality of transaction types; calibrating a performance model of the application in accordance with the received performance data; and calculating an expected performance of the application by the system based on the performance model calibration and the received performance data.